Male sperm whales produce loudest communication sounds ever measured in any mammal - Phys.org

Marina: Welcome to Deep Voices — I am so glad you're here. I'm Marina, a marine biologist and science communicator who has spent most of her adult life completely, hopelessly in love with whales and dolphins, and honestly I have zero regrets about that life choice. Marina: Before we dive in — and we are going to dive deep today — a huge thank you to our sponsors: Ada, who helps businesses and organizations integrate A I into their workflows in ways that actually make sense; Ago Consulting, pronounced "Ahh-Go," your go-to team for silicon development consulting, from A I all the way to SoC; and Zen Semiconductor, an umbrella company with a remarkable portfolio spanning the silicon industry. We couldn't do this without them. Marina: Today on Deep Voices — sperm whales are making sounds so loud they defy belief, we're going to talk about what that means. A I is getting genuinely good at decoding animal communication, and scientists are starting to ask questions we never thought we'd be able to ask. And we're going to spend some time in the warm coastal waters off Florida, where sixty-two hours of underwater listening revealed something beautiful about where dolphins actually live their lives. Let's go. Marina: Okay, thread one — Voices of the Deep. And I want to start with something that stopped me cold when I read it this week. Marina: Male sperm whales produce the loudest communication sounds ever measured in any mammal. Any mammal. That includes us, that includes blue whales, that includes anything that has ever lived on this planet and breathed air. The sounds these animals make have been measured at around two hundred and thirty decibels. To put that in perspective — a jet engine at close range is around one hundred and forty decibels. A rock concert is maybe one hundred and ten. These whales are operating on a completely different scale. Marina: Now, sperm whales make a kind of sound called a click. And when we say click, don't picture the gentle little tick of a computer mouse. Picture something that can travel for kilometers through the ocean, that can literally stun prey — giant squid, deep-sea fish — before the whale even touches them. The sperm whale's head, which can make up a full third of its entire body length, is essentially the most sophisticated biological sound system ever evolved. Marina: Inside that enormous head is a structure called the spermaceti organ — which is where those old whalers got confused and thought it was full of sperm, hence the name, but it's actually a series of oil-filled sacs that act like acoustic lenses. The whale generates a click at the front of its head, bounces it back and forth through these sacs, focuses it, amplifies it, and then fires it out into the ocean like a sonar beam. It is extraordinary bioengineering that took millions of years to develop. Marina: But here's what's newly fascinating — and this is where researchers are now turning their attention. Those clicks aren't just for hunting. They're also for talking. Sperm whales produce patterned sequences of clicks called codas — and codas are social. They happen when whales are together, greeting each other, bonding, interacting. Different groups of sperm whales, what we might call clans, have their own distinct coda repertoires. Dialects, essentially. A whale from the Pacific doesn't coda quite the same way as a whale from the Caribbean. Marina: And now, with new research suggesting that male sperm whales — who live more solitary lives than the tight-knit female groups — are producing these enormous, record-breaking sounds during communication, not just hunting, we have to ask ourselves: what exactly are they saying, and to whom, and across how many miles of open ocean? Marina: That question is not rhetorical. Scientists are genuinely working on it. And that brings us perfectly into thread two. Marina: Culture and Decoding. Because this week, Nature — one of the most prestigious scientific journals in the world — published a piece about how A I is decoding the calls of the wild. And it is one of the most exciting developments in my entire career as someone who studies these animals. Marina: Here's the thing about animal communication that makes it so hard to study. It's not like learning a foreign language where you can sit down with a dictionary and a grammar book. Animal vocalizations are enormous in quantity, incredibly complex in structure, and happen in environments — underwater, in rainforests, in the middle of the night — that are really hard for humans to monitor continuously. You could spend a lifetime recording whale sounds and still only scratch the surface of the data. Marina: Enter A I. Specifically, the kind of machine learning tools that can listen to thousands of hours of recordings, find patterns that no human ear or brain could detect, and start to map the structure of a communication system without anyone telling it what to look for first. This is called unsupervised learning, and it is changing everything. Marina: One of the most ambitious efforts in this space is Project CETI — the Cetacean Translation Initiative. CETI is a collaboration of marine biologists, A I researchers, linguists, and cryptographers, and their goal is breathtaking: to record, analyze, and ultimately decode the communication of sperm whales. Specifically those coda clicks I mentioned earlier. They're deploying underwater microphones, attaching non-invasive acoustic tags to whales off the island of Dominica, and feeding the resulting data into some of the most sophisticated A I systems on the planet. Marina: What makes sperm whale codas a compelling starting point is that they have structure. They're not random. Each coda is a pattern of clicks — maybe three clicks, maybe ten, at specific rhythms and intervals. Researchers have already catalogued hundreds of distinct coda types. And now A I tools are being used to look for something deeper: does the context in which a coda appears change its meaning? Are there combinations of codas that function like sentences? Is there something in there that works like grammar? Marina: We don't have the answer yet. I want to be really honest about that — we are not at the point where we can say "this coda means I'm hungry" or "that sequence means come meet me here." But the fact that we are now asking those questions with tools powerful enough to potentially answer them? That is genuinely new. That is a frontier that didn't exist even ten years ago. Marina: The Nature piece also highlights that this isn't just happening with whales. A I is being used to decode prairie dog calls — and one researcher found what appeared to be descriptive words, where prairie dogs were making different sounds for "tall human in yellow shirt" versus "short human in blue shirt." It's being used with Egyptian fruit bats, with crows. The animal communication revolution is broad. But for me, it's the cetaceans that feel most electric, because the complexity we already know is there, in those clicks and songs and whistles, suggests something vast waiting to be understood. Marina: And what I love about all of this is the collaboration at its heart. Marine biologists who have spent decades in the field, in the water, building relationships with these whale families — working alongside computer scientists who have never seen a whale in person but can hold a million data points in their heads. That's a beautiful thing. Different kinds of intelligence, working together to understand another kind of intelligence entirely. Marina: Thread three. A cetacean-and-people story — and this one comes from the warm, sun-lit coastal waters of Florida. Marina: Researchers recently published findings from a study where they deployed underwater hydrophones — sensitive underwater microphones — and recorded sixty-two continuous hours of ocean soundscape in Florida's coastal waters. Sixty-two hours. Just listening. And what they found was remarkable: distinct acoustic hotspots, places in the water where dolphin sounds were consistently concentrated, revealing for the first time exactly where bottlenose dolphins were spending their time, socializing, feeding, and communicating. Marina: Now, why does that matter? Florida's coastal waters are busy. Boating traffic, fishing, coastal development, tourism — these waterways are shared in complicated ways between humans and dolphins. And bottlenose dolphins, who are highly social, who use their signature whistles to maintain contact with their family groups, who teach their young the specific whistle that belongs to them alone — these dolphins need certain places to be what they need to be. Calm enough to communicate. Rich enough in fish. Safe enough for calves. Marina: The signature whistle, by the way, is one of my favorite things in all of animal behavior. Every bottlenose dolphin develops its own unique whistle — it's called a signature whistle — within the first few months of life. And it stays with that dolphin for their entire life, sometimes fifty years or more. It's their name. Dolphins call out their own signature whistle when they want to be found, and they copy the signature whistles of individuals they're close to — their mothers, their closest companions — as a way of saying, essentially, "I'm thinking of you. I'm here." Marina: Mothers and calves exchange signature whistles constantly. There are recordings of mother dolphins whistling almost nonstop in the hours before they give birth — researchers believe they're imprinting their signature on the newborn before it even arrives in the world. That is not metaphor. That is documented behavior that makes my heart do things every single time I think about it. Marina: So when we know this — when we know how deeply communication is woven into every part of a dolphin's life — the finding that certain coastal locations are acoustic hotspots for these animals becomes urgent. It tells us where the dolphins most need protection. Where boat speed restrictions matter most. Where noise pollution from watercraft or development could genuinely disrupt the social fabric of a dolphin community. Marina: This kind of acoustic monitoring is increasingly becoming a conservation tool. Instead of sending a researcher out in a boat to count fins — which is valuable but limited — you drop a hydrophone, you let it listen, and you get a picture of animal presence and behavior that is continuous, non-invasive, and remarkably detailed. The ocean tells you who's there, and when, and how active they are, through sound. You just have to learn to listen. Marina: And actually, that's a perfect note to end on, isn't it. Learning to listen. Marina: Here's what I keep coming back to after a week of these stories. We live alongside animals who are singing to each other across miles of open ocean. Who give their children names. Who pass down dialects and cultural traditions through generations. Who produce sounds so powerful they beggar belief. And for most of human history, all of that happened in the darkness of the sea, completely unheard by us. Marina: But now — with hydrophones and A I and decades of patient field work by scientists who gave their careers to being in the water with these animals — we are beginning, just beginning, to hear them. Really hear them. And whatever we find when we truly understand what they're saying, I suspect it is going to change us. Marina: Deep Voices, brought to you by Ada, Ago Consulting, and Zen Semiconductor. Thank you for listening, truly — this community of curious, ocean-loving people is everything to me. If today's episode moved you or blew your mind or made you want to know more, please subscribe, leave a review, and share it with someone who loves the sea or just loves a good story about something smarter than we expected. Marina: Show notes are waiting for you with links to all the studies and sources from today's episode. Until next time — stay curious, stay humble, and keep listening for voices in the deep.